16 flood insurance claims·$392,829 paid·8 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Lyman County, South Dakota. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Standard river flooding and flash flooding from summer thunderstorms dominate the flood risk profile in Lyman County, SD, which recorded 26 standard floods and 12 flash flood events—including 2 deaths—over the last 30 years. Recent events illustrate this varied threat, such as an August 2025 flash flood where heavy rainfall from scattered thunderstorms caused a trained spotter to report water flowing over roads in West Brule. Additionally, above-normal temperatures drove rapid snow melt that caused minor rural flooding along Medicine Creek in February 2024, while heavy rainfall caused Cedar Creek near Presho to briefly exceed flood stage and impact low-lying pasture lands in October 2023.
National Flood Insurance Program claims data indicates that properties in Zone A experienced 14 claims with an average payout of $20,825 and an average recorded water depth of 6 inches. Properties designated as Zone D recorded 2 claims with an average payout of $113,113 and an average recorded water depth of 9 inches. Homeowners, real estate agents, and journalists should pay the most attention to properties situated near creeks, rivers, and low-lying areas prone to rapid snow melt or intense summer thunderstorms.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
In flood insurance claims here that reported a flood depth, the average was 6 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2019, with 13 claims and $275,574 paid, the year of Severe Winter Storm, Snowstorm, and Flooding and Severe Storms and Flooding.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
10 NOAA storm reports from Lyman County describe what happened, in the words of the forecasters who covered it. Read the South Dakota flood stories →
30 federal disaster declarations since 1976, 8 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms And Flooding | May 21, 2019 |
| Severe Winter Storm, Snowstorm, And Flooding | Mar 13, 2019 |
| Severe Storms, Tornadoes, Straight-line Winds, And Flooding | Jun 17, 2015 |
| Flooding | Mar 11, 2011 |
| Flooding | Mar 10, 2010 |
| Severe Winter Storm And Snowstorm | Dec 23, 2009 |
| Severe Storms And Flooding | Jun 2, 2008 |
| Hurricane Katrina Evacuation | Sep 6, 2005 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
38 since 1996: 12 flash floods and 26 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Aug 3, 2025 | — |
| Flash Flood | Jun 20, 2024 | — |
| Flood | Feb 8, 2024 | — |
| Flood | Oct 13, 2023 | — |
| Flood | May 26, 2019 | — |
| Flood | Mar 26, 2019 | — |
| Flood | May 22, 2019 | — |
| Flood | Mar 14, 2019 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Aug 3, 2025. Scattered thunderstorms on the afternoon of August 3rd produced large hail and caused flash flooding in Lyman County. Heavy rainfall from these storms led to a trained spotter reporting water flowing over roads in West Brule.
Flash Flood · Jun 20, 2024. Thunderstorms with heavy rainfall produced flooding across a broad swath of Lyman, Buffalo and Hand counties. In Lyman county, 7.46 inches was observed at a weather station 6 miles south southwest of Oacoma, while the South Dakota State University mesonet station near Oacoma recorded 5.51 inches. A CoCoRaHS observer 5 miles west southwest of Oacoma also observed 4.79 inches. In nearby Buffalo county, 3.56 inches o…
Flood · Feb 8, 2024. Above normal temperatures resulted in rapid snow melt across central South Dakota. This snow melt resulted in a rise in river levels of Medicine Creek which lasted for about a day before steadily receding. A peak crest of 1667.53 was observed on the morning of 2/9, with only minor rural flooding.
Flood · Oct 13, 2023. The Cedar Creek near Presho briefly rose above the 12 foot flood stage during the morning of October 13th. The flooding was caused by 3 to 5 inches of heavy rainfall. The creek crested at 12.36 feet during the mid morning hours before falling below flood stage at 1:30 PM CDT. The flood waters impacted low-lying pasture lands.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Lyman County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.